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  <title>Document</title>
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  <!-- 1. 准备容器 -->
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    <!-- 4. 渲染数据 -->
    <table width="800px" style="text-align: center; margin: 0 auto;" border="1">
      <caption>欢迎光临_vue开发的收银系统_水果店</caption>
      <tr>
        <th>苹果 10￥/斤,折扣< 8折>
        </th>
      </tr>
      <tr>
        <td>请输入你要购买的斤数 <input type="number" v-model.number="weight">
        </td>
      </tr>
      <tr>
        <td><button @click="pay">结账买单~</button>
        </td>
      </tr>
      <tr>
        <td>
          结账单：
          <span>总价：{{price}}￥元</span>
          <span>折后价：{{price * 0.8}}￥元</span>
          <span>省了：{{price * 0.2}}￥元</span>
        </td>
      </tr>
    </table>
  </div>
  <!-- 2. 引入vuejs -->
  <script src=" https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
  <script>
    // 3. 创建Vue实例
    const app = new Vue({
      el: '#app',
      data: {
        weight : 0,
        price : 0
      },
      methods : {
        pay(){
          this.price = this.weight * 10
        }
      }
    })
  </script>
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